Eleven people, including nine high school students, died on a highway in the central Mexican state of San Luis Potosi after their vehicle collided with a freight truck's trailer.
A trailer broke off the back of the truck and hit the vehicle with the students near the town of Rayon in the northern part of the state, the San Luis Potosi ministry of public security said in a Facebook post. Two adults were also killed.
The truck driver was not hurt and has been detained while the accident, which happened on Tuesday, is investigated, the ministry said.
Early reports suggested the students were returning from taking a university entrance exam in the neighboring state of Zacatecas, the posting by the public security ministry said.